The addition of a 10th furnace will improve the efficiency of the plant and increase its production capacity.

Ineos official John McNally said: “Our plans to invest in the UK with the further expansion of our plant at Grangemouth has been made possible because we now have access to the raw materials that we need.

“The successful completion in 2016 of our project to bring to Grangemouth plentiful supplies of competitive US shale gas ethane over a long-term agreement, has breathed new life into the plant.

“Having additional furnace capacity will provide a range of future opportunities, not just for Ineos and for the site, but also for the heartlands of manufacturing in Scotland and the North East and North West of England.”